INTERNATIONAL HYDROGRAPHIC ORGANIZATION IHO STANDARDS FOR HYDROGRAPHIC SURVEYS 5th Edition, February 2008 Special Publication No. 44 Published by the International Hydrographic Bureau MONACO INTERNATIONAL HYDROGRAPHIC ORGANIZATION IHO STANDARDS FOR HYDROGRAPHIC SURVEYS 5th Edition, February 2008 Special Publication No. 44 published by the International Hydrographic Bureau 4, quai Antoine Ier B.P. 445 - MC 98011 MONACO Cedex Principauté de Monaco Tel : (377) 93.10.81.00 Fax : (377) 93.10.81.40 E-mail: [email protected] Website: www.iho.int © Copyright International Hydrographic Organization [2008] This work is copyright. Apart from any use permitted in accordance with the Berne Convention for the Protection of Literary and Artistic Works (1886), and except in the circumstances described below, no part may be translated, reproduced by any process, adapted, communicated or commercially exploited without prior written permission from the International Hydrographic Bureau (IHB). 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IHO STANDARDS FOR HYDROGRAPHIC SURVEYS (S-44) 5th Edition February 2008 CONTENTS Page Preface ............................................................................................................................... 1 Introduction ............................................................................................................................... 3 Chapter 1 Classification of Surveys ....................................................................................... 5 Chapter 2 Positioning ............................................................................................................. 7 Chapter 3 Depths .................................................................................................................... 8 Chapter 4 Other Measurements ............................................................................................ 11 Chapter 5 Data Attribution ................................................................................................... 12 Chapter 6 Elimination of Doubtful Data .............................................................................. 14 Table 1 ............................................................................................................................. 15 Glossary ............................................................................................................................. 17 Annex A Guidelines for Quality Control ............................................................................ 21 Annex B Guidelines for Data Processing ........................................................................... 25 NB: Annexes A and B will be removed from this document when the information contained in them is fully included in IHO Publication M-13 (Manual on Hydrography) i IHO STANDARDS FOR HYDROGRAPHIC SURVEYS (S-44) 5th Edition February 2008 PREFACE This publication, “Standards for Hydrographic Surveys” (S-44), is one of the series of standards developed by the International Hydrographic Organization (IHO) to help improve the safety of navigation. Formal discussions on establishing standards for hydrographic surveys began at the VIIth International Hydrographic Conference (IHC) in 1957. Circular Letters to Member States in 1959 and 1962 reported on the views of Member States and the VIIIth IHC in 1962 established a Working Group (WG) comprising 2 members from the USA, 1 from Brazil and 1 from Finland. The WG communicated by mail and held two meetings in conjunction with the IXth IHC in 1967 and prepared the text for Special Publication No S-44. The 1st Edition of S-44 entitled “Accuracy Standards Recommended for Hydrographic Surveys” was published in January 1968 the Foreword to which stated that “…hydrographic surveys were classed as those conducted for the purpose of compiling nautical charts generally used by ships” and “The study confined itself to determining the density and precision of measurements necessary to portray the sea bottom and other features sufficiently accurately for navigational purposes.” Over subsequent years technologies and procedures changed and the IHO established further WGs to update S-44 with the 2nd Edition published in 1982, the 3rd in 1987 and the 4th in 1998. Throughout these revisions the basic objectives of the publication have remained substantially unchanged and this remains so with this 5th Edition. The Terms of Reference for the WG established to prepare the 5th Edition of S-44 included inter alia: a desire for clearer guidance regarding sea floor features and listed a number of concerns including system capabilities for detecting features and the characteristics of features to be detected. The WG concluded that S-44 sets minimum standards for surveys conducted for the safety of surface navigation. The WG considered it to be the responsibility of each national authority to determine the precise characteristics of features to be detected relevant to their organization and to determine the ability of particular systems and their procedures to detect such features. The WG further concluded that the design and construction of targets used to demonstrate system detection capabilities is the responsibility of national authorities. The reference to cubic features > 1 or 2 metres in size used in these Standards provides a basis for understanding that features of at least this size should be detected. The principal changes made from the 4th Edition are: The division of Order 1 into 1a where a full sea floor search is required and 1b where it is not required. The removal of Order 3 as it was considered that there was no longer a need to differentiate this from Order 2. The replacement, in most cases, of the words “accuracy” and “error” by “uncertainty”. Errors exist and are the differences between the measured value and the true value. Since the true value is never known it follows that the error itself cannot be known. Uncertainty is a statistical assessment of the likely magnitude of this error. This terminology is increasingly being used in measurement: see ISO/IEC 98: 1995 “Guide to the expression of uncertainty in 1 IHO STANDARDS FOR HYDROGRAPHIC SURVEYS (S-44) 5th Edition February 2008 measurement” (due to be updated in 2008) and ISO/IEC 99:2007 “International Vocabulary of Metrology – Basic and general concepts and associated terms (VIM). The Glossary has been updated and some terms which the WG consider fundamental to the understanding of these Standards are repeated in the Introduction. The WG considered that information on “How to Survey” was not appropriate to these Standards and this information has been removed from the 5th Edition. However the WG acknowledges the usefulness of this guidance and the information has been retained in two annexes. The WG recommends that this information should be transferred to IHO Publication M-13 (Manual on Hydrography) at which time the annexes should be removed from S-44. A minimum spot spacing for bathymetric LIDAR has been included in Table 1 for Order 1b surveys where full sea floor search is not required. Finally it was the view of the WG that S-44 provides “Standards for Hydrographic Surveys” and that it is the responsibility of individual Hydrographic Offices / Organizations to prepare “Specifications” based on these Standards. Specifications will be more system specific and as such will be quite dynamic as systems change. 2 IHO STANDARDS FOR HYDROGRAPHIC SURVEYS (S-44) 5th Edition February 2008 INTRODUCTION This publication is designed to provide a set of standards for the execution of hydrographic surveys for the collection of data which will primarily be used to compile navigational charts to be used for the safety of surface navigation and the protection of the marine environment. It must be realised that this publication only provides the minimum standards that are to be achieved. Where the bathymetry and expected shipping use requires it, hydrographic offices / organisations wishing to gather data may need to define more